I propose to study the anaerobic-stress response in Zea mays. Anaerobic treatment dramatically alters the pattern of gene expression in maize seedlings. During anaerobiosis there is an immediate repression of pre-existing protein synthesis followed by an induction of gene expression involving the synthesis of approximately twenty anaerobic-specific proteins. Among these anaerobic proteins (ANPs) are the alcohol dehydrogenase (ADH) isozymes encoded by the Adhl and Adh2 genes. The anaerobic-stress response of maize offers a unique opportunity to characterize the regulatory components of a family of twenty genes which are coordinately expressed. The overall aim of this proposal is to use the powerful tools of genetics and recombinant DNA technology to analyze this highly regulated response. I plan to identify and characterize the genes involved in a plant's response to an environmental stress which would occur in nature during flooding. These genes include the remaining anaerobic- specific genes, and those encoding the transition polypeptides (TPs), which are a group of protein synthesized preferentially during the first few hours of anaerobic treatment. It also includes possible trans-acting genes that might control this physiological response. Sequence comparisons and expression studies will be carried out to identify regions within the anaerobic genes that may be responsible for the induction of transcription and the selective translation of their mRNAs during anaerobiosis. It is anticipated that these studies will contribute toward the understanding of the eukaryotic gene as a functional unit and to some aspects of differential gene expression.